The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Laws to protect journalists passed in WA

Journalists in Western Australia are now legally protected from being compelled to reveal their sources, unless it's in the public interest, after so-called shield laws passed through state parliament.

WA Attorney General Michael Mischin said the Evidence and Public Interest Disclosure Legislation Amendment Bill 2011 fulfilled the state government's election commitment to introduce protections for journalists in respect of their informants.

"A journalist who has promised not to reveal their source's identity will not be able to be compelled to do so, unless the public interest clearly requires it," Mr Mischin said.

"Journalists will now be able to work in the knowledge that they are legally protected from having to disclose the identity of their sources."

The bill also protects other professionals who receive confidential information.

"This bill recognises the ethical obligation professionals owe their clients to preserve confidentiality and balances that against their legal obligation to give evidence when required to do so by a court or tribunal," Mr Mischin said.

"Further, the bill serves the public interest of preserving appropriate confidentiality while recognising that journalists play a vital role in ensuring the free flow of facts and information to the public."